Pheromones are chemicals released by living organisms that send information to other organisms of the same species via scent. Pheromones are released in response to stress, alarm, danger, sexual fertility, and in other behavioral contexts. Pheromones, by definition and according to evolutionary theory, are species-specific, that is, they are effective in eliciting an innate response only in members of the same species.
One of the best characterized mammalian pheromones is the rabbit nipple “search pheromone.” Sensed by rabbit pups via their main olfactory system, the pheromone elicits a characteristic nipple search behavior that quickly results in the location of a nipple. (See Distel, H. and Hudson, R. (1985), “The contribution of the olfactory and tactile modalities to the performance of nipple-search behavior in newborn rabbits.” J. Comp. Physiol. [A] 157, 599-605) This guidance cue is particularly important for rabbits, as a doe only nurses her pups for around four minutes once a day and the quick location of a nipple in the face of sibling competition is vital for survival. This “search pheromone” has recently been shown to be a single molecule, 2-methylbut-2-enal (Schaal et al., Chemical and behavioural characterization 46028352.1 of the rabbit memory pheromone, Nature, 424:68-72, 2003), which is produced in rabbit milk and is sufficient to elicit full nipple search and grasping behavior when presented on its own at concentrations as low as 10 ng/mL.
Chemicals that provide interspecies communication are called allelochemicals. Some compounds are known to be a pheromone in one species, but have been observed to have strong behavioral effects in other species. For example, chemicals produced and released by one species that affect the behavior or physiology of another species to the benefit of the originator but not the receiver are known in the art as allomones (See Grasswitz, T. R. and G. R. Jones (2002). “Chemical Ecology”. Encyclopedia of Life Sciences. John Wiley & Sons, Ltd. doi:10.1038/npg.els.0001716). The production of allomones in natural environments has been mainly observed in plant species, which utilize allomones for example to protect plants against insect herbivores.
A kairomone is another known allelochemical. It is emitted by one species and benefits another species, but does not benefit and often harms the emitter. The production of kairomones in natural environments has been mainly observed in insect species. For example, the Ponderosa Pine tree produces a terpene called myrcene when the Western pine beetle damages the tree. The emission of this chemical then lures more beetles to the tree (See Wyatt, T. D. (2003). Pheromones and Animal Behaviour: Communication by Smell and Taste, First Edition (Cambridge, UK: Cambridge University Press).
A synomone is an allelochemical produced and released by one species that benefits both the emitter and receiver. For example, plants emit odors that work to attract bees. The bees are attracted to the plants to feed and then the bees take the pollen to fertilize other plants/flowers.
Accordingly, the allelochemicals known in the art involve the observation of chemicals produced by one species having an effect on another species to the benefit and/or detriment of the emitting or receiving species. What is described is an allelochemical that affects the behavior and/or physiology of another species (i.e., the receiving species) without additionally having a beneficial or harmful effect on the emitting species and having a novel or unrelated behavioral or physiological effect on the receiving species.
For instance, while domestic dogs are known to bark as part of their normal method of communication, dogs may show excessive barking/jumping/mobbing/begging in response to external cues or due to boredom. Mobbing includes repetitive barking and jumping. Certain dogs will bark and jump in an excitable manner when they hear or see people, animals, vehicles, or machines. One theory is that excessive barking is part of the “mobbing” behavior that pack animals have when they attack a prey species (Lord et al., Barking and mobbing., Behav. Processes, 81:358-368, 2009).
Methods used in the art to stop the barking/jumping/begging syndrome have included shock collars, odor sprays, and loud noises, all of which work by startling or distracting the dog from engaging in the undesirable behavior. Dog appeasing pheromones, including synthetic compositions believed to replicate certain calming pheromones emitted by dogs, have also been used in the art to treat certain behavioral problems in dogs, but to date, have not been successful in alleviating the barking/jumping syndrome exhibited by certain dogs. Moreover, the pheromones used in the art have not been directed for use with animal species other than the species from which the pheromones are emitted.
Accordingly, it would be desirable to provide methods and compositions comprising a compound known to be a pheromone in one species to positively modify animal behavioral problems in a variety of different vertebrate species. In particular, there is a need in the art for use of an INTEROMONE® to calm, sedate, reduce anxiety, or otherwise positively modify the behavior of a variety of vertebrate species, including the barking/jumping/begging syndrome exhibited by some dogs or to calm anxious dogs or cats or other vertebrate species.